Many conventional receivers “wake up” periodically to determine if any messages (pages) are scheduled to be transmitted to the receiver or whether the receiver is to communicate with another node within the network. If no messages are scheduled, or if the receiver need not communicate with another network node, the receiver will power down in order to extend the battery life of the receiver. In order to determine whether any action needs to be taken by the receiver, the receiver “listens” to a beacon to determine if the receiver's address is contained within the beacon's transmission. When the address of the receiver is not located within the beacon's transmission, the receiver can be certain that no action needs to be taken by the receiver, and may immediately go to sleep. After a predetermined time period, the receiver will awake again, “listen” to the beacon, and decide whether to stay awake for reception of a message, or to again go to sleep.
In addition to address information, the beacon may contain other information used by network nodes. For example, the beacon may comprise operating parameters such as control information for the network, including status information, types and methods of security employed (message encryption and integrity codes), beacon intervals, etc.
For illustration purposes, one such beacon network developed with such power-saving capabilities is the next generation Code-Division Multiple-Access (CDMA) cellular communication system, more commonly referred to as cdma2000, or Wideband CDMA. As illustrated in FIG. 1, cdma2000 utilizes a plurality of 20 millisecond (ms) synchronous frames 102 (shown as F0, F1, F2, . . . , FK). Frames 102 are transmitted during a periodically occurring time span corresponding to a transmission cycle that has a predetermined duration (e.g., 1.28*2N seconds, where N is zero or a positive integer). A network node within a cdma2000 system is assigned a group of four frames (referred to as a slot) in which all messages for the particular network node are to be transmitted. A network node operating as such is said to be operating in a “slotted mode.” Slotted mode operation allows a cdma2000 network node to power up for a single assigned paging slot every 1.28*2N seconds to determine if any messages are to be transmitted to the receiver.
In order to conserve power, all addresses for network nodes that are to receive messages during a particular slot are broadcast prior to broadcasting the message. If a network node's address is not broadcast within this beacon, the network node can power down for the remainder of the slot. FIG. 2 shows slot 200 having four frames. As shown, a first portion 201 of slot 200 contains address information for all network nodes that have page data within slot 200. A particular network node assigned to slot 200 will awake during the transmission time for slot 200. The network node will receive the first frame, and if the network node's address is not contained within the first portion 201 of slot 200, the network node will power down prior to receiving the rest of slot 200.
Although prior art schemes greatly extend battery life, it is recognized that battery life can be further extended by reducing the amount of time that the receiver spends awake. With battery life being one of the driving factors when choosing consumer products, any increase in batter life is extremely advantageous to equipment manufacturers. Therefore, a need exists for a method and apparatus for further extending battery life for receivers operating within a beaconing network.